The socio-endocrine regulation of human growth.

ABSTRACT

AIM: Growth is a multifarious phenomenon that has been studied by nutritionists, economists, paediatric endocrinologists; archaeologists, child psychologists and other experts. Yet, a unifying theory of understanding growth regulation is still lacking. METHOD: Critical review of the literature. RESULTS: We summarise evidence linking social competition and its effect on hierarchies in social structures, with the neuronal networks of the ventromedial hypothalamus and body size. The endocrine signalling system regulating growth hormone, Insulin-like-Growth-Factor1 and skeletal growth, is well conserved in the evolution of vertebrata for some 400 million years. The link between size and status permits adaptive plasticity, competitive growth and strategic growth adjustments also in humans. Humans perceive size as a signal of dominance with tallness being favoured and particularly prevalent in the upper social classes. CONCLUSION: Westernised societies are competitive. People are tall, and "open to change." Social values include striving for status and prestige implying socio-economic domination. We consider the transition of political and social values following revolutions and civil wars, as key elements that interact with the evolutionarily conserved neuroendocrine competence for adaptive developmental plasticity, overstimulate the hypothalamic growth regulation and finally lead to the recent historic increases in average height.